Re: Canvas shortcomings

[Lauris Kaplinski <lauris ximian com>]

On 19 Jun 2001 13:34:49 -0400, Mark wrote:
> On 19 Jun 2001, Owen Taylor wrote:
> >  - Basic API is painting, not a canvas. There is no heirarchy
> >    of objects, or idea of having the entire scene in memory.
> > 
> >  - But instead of a PS-like "moveto lineto" scheme, you 
> >    lightweight shape objects that you can create for primitives
> >    like circles and rectangles.
> > 
> 
> The PS-like operators come in handy when you want to describe generalized
> paths. Actually, the API that is closest to what you describe, Java2D, has
> such an object to describe paths in that way.
> 
> http://java.sun.com/j2se/1.3/docs/api/java/awt/geom/GeneralPath.html
> 
> It would probably be nice to have both general paths and primitive shapes,
> instead of either or.

Very similar problem is solved in gnome-print. The core API is 
basically:

fill_path
stroke_path
clip_path
draw_image

But in frontend you can use PostScript-like operators to construct 
paths, set colors etc. It is extremely trivial to program, so there
certainly could be one.
The biggest problem with PostScript-like API is, that you have to
document it damn well. There are loads of questions, that have to
be answered soewhere:

Is there default color, or is drawing without def. color error?
Do filling shape close open paths.
etc.
One can just take PostScript conventions, of course.

Best wishes,
Lauris Kaplinski